Which top schools offer a double major in Economics/Business and Computer Science?

So this is a more complicated question than it might seem, and because of that complexity I wouldn't let it dictate your high school schedule. Economics and Business aren't interchangeable at most places because they'll be offered in different undergraduate colleges (for example, a College of Arts & Sciences vs. a College of Business within a larger university). CS will often be offered in both an Arts & Sciences college and a College of Engineering. The basic rule is that you can double major with programs in the same undergrad college, but would need to apply for a dual degree program to do two majors in separate colleges.

To go specifically into this question, for Economics (NOT Business) and Computer Science, you're going to find a lot of schools with that as an available double major. To double major in two subjects, those subject usually need to be in the same undergraduate college, and many schools (e.g. Cornell) will have Economics and Computer Science as available majors in their College of Arts & Sciences.

However, if you want to do Computer Science in an engineering college (some schools offer the major in both their general undergraduate college and College of Engineering, sometimes with different overall requirements), you would need to apply to a dual-degree program.

The same goes for combining Business with (any) Computer Science, because Business programs are typically in their own undergraduate college. Dual degree programs usually have more specific requirements and might require 5 years of study instead of 4, which obviously comes at a higher cost.

There are a couple of schools with Business/CS (or related) programs, like WashU (https://admissions.wustl.edu/academics/special-programs/joint-degree-in-business-and-computer-science/) and Penn's M&T program (https://ugrad.seas.upenn.edu/student-handbook/programs-options/dual-degrees-and-special-programs/). You could look into these if you're more curious.